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Village Agriculture, Horticulture and Sericulture Assistant · Chapter 14

Environmental science and disaster management for agriculture

What to remember

  • Environment is the sum of living (biotic) and non-living (abiotic) surroundings. Farming depends on healthy soil, water, air and biodiversity, and also changes them.
  • Energy in an ecosystem flows in one direction and is lost at each trophic level (the 10% law), while nutrients cycle.
  • Disaster management has four stages: prevention and mitigation, preparedness, response, and recovery. In India the Disaster Management Act 2005 sets up the NDMA, State and District authorities.

Ecosystem and biodiversity

  • Ecosystem = community of living things plus the non-living environment, with energy flow and nutrient cycling. Types: forest, grassland, desert, aquatic, and agro-ecosystem.
  • Producers (green plants) make food by photosynthesis. Consumers are primary (herbivores), secondary and tertiary (carnivores). Decomposers (bacteria, fungi) recycle nutrients.
  • Food chain is a single path of feeding; food web is many linked chains.
  • 10% law: about 10% of energy passes to the next level. If producers hold 10,000 J, primary consumers get 1,000 J, secondary 100 J, tertiary 10 J.
  • Biodiversity levels: genetic, species and ecosystem. In-situ conservation (national parks, sanctuaries, biosphere reserves) protects species in their habitat; ex-situ (gene banks, zoos, botanical gardens, seed banks) protects them outside. Threats: habitat loss, over-use, invasive species, pollution and climate change.
  • Andhra Pradesh has the Eastern Ghats forests, coastal mangroves such as Coringa, and wetlands such as the Kolleru lake (a Ramsar site) and Pulicat lagoon.
  • Biosphere reserve zones: core, buffer and transition.

Pollution and agriculture

PollutionAgricultural cause or effect
WaterRun-off of fertiliser and pesticide; eutrophication (excess nitrogen and phosphorus cause algal bloom and oxygen loss)
SoilOver-use of agrochemicals, salinity, plastics, industrial waste
AirBurning of crop residue, dust, methane from paddy fields and livestock, ammonia from fertiliser
PesticideBio-magnification: concentration rises along the food chain, so top consumers carry the most

Key terms: BOD (biochemical oxygen demand) is oxygen needed by microbes to break down organic matter in water; high BOD means polluted water. Dissolved oxygen falls when pollution rises. Acid rain has pH below 5.6 and is formed by oxides of sulphur and nitrogen.

Worked pH example: pH = −log[H⁺]. If [H⁺] = 10⁻⁵ mol/L, pH = 5. A change of one pH unit means ten times change in H⁺ concentration; pH 5 is ten times more acidic than pH 6.

Agricultural responses: Integrated pest management, balanced and soil-test-based fertiliser use, organic manure, biofertilisers, crop residue incorporation instead of burning, drip and sprinkler irrigation, agroforestry, and soil conservation (contour bunds, terracing, mulching, cover crops, grass strips).

Soil problems: erosion by water and wind, salinity and alkalinity (gypsum is used for sodic soil), acidity (lime) and waterlogging. Conservation agriculture rests on minimum tillage, residue cover and crop rotation.

Climate change and global issues

GasMain agricultural source
Carbon dioxide (CO₂)Fossil fuel, land clearing, residue burning
Methane (CH₄)Paddy fields under flood, ruminant animals, manure
Nitrous oxide (N₂O)Nitrogen fertiliser use and soil
  • Greenhouse effect keeps the earth warm; global warming is the rise caused by extra greenhouse gases.
  • Effects on farming: higher temperature, uneven rain, more pests, sea-level rise on the coast, and reduced yield in heat-sensitive crops.
  • Adaptation (drought-tolerant varieties, changed sowing dates, crop insurance) differs from mitigation (cutting emissions, alternate wetting and drying in paddy, better manure management).
  • Ozone layer in the stratosphere shields from UV-B; CFCs damage it. The Montreal Protocol (1987) controls ozone-depleting substances. The UNFCCC is the climate convention; the Paris Agreement (2015) aims to keep temperature rise well below 2°C. Kyoto Protocol came earlier.
  • Sustainable development means meeting present needs without harming future generations.
  • Common legal names: the Environment (Protection) Act 1986, Water Act 1974, Air Act 1981, Wildlife (Protection) Act 1972, Forest (Conservation) Act 1980, Biological Diversity Act 2002 and the National Green Tribunal (set up in 2010).

Disasters affecting agriculture

  • Drought: shortfall in rain. A meteorological drought is declared when seasonal rainfall deficit is large; agricultural drought is when soil moisture is too low for crops.
  • Flood: excess water, waterlogging, silt and crop loss.
  • Cyclone: strong winds, storm surge and heavy rain; the east coast, including the Andhra coast, is prone to cyclones from the Bay of Bengal.
  • Others: heat wave, cold wave, hailstorm, pest outbreak, locust attack and earthquake.

Agricultural disaster measures:

  • Before: contingency crop plans, short-duration and drought-tolerant varieties, seed banks, water harvesting, drainage, early warning from the India Meteorological Department (IMD), weather-based agro advisories, crop insurance.
  • During: protect seed and stock, harvest early where possible, drain flood water, support livestock.
  • After: replanting with short-duration crops, input assistance, damage survey, relief and insurance claims.
  • Pradhan Mantri Fasal Bima Yojana (PMFBY) gives crop insurance against natural calamities, pests and diseases; farmers pay a low fixed premium.
  • Contingency crops in drought: pulses, millets and short-duration crops; in flood: rice varieties tolerant to submergence.

Disaster Management institutions

LevelBody
NationalNational Disaster Management Authority (NDMA), headed by the Prime Minister
StateState Disaster Management Authority (SDMA), headed by the Chief Minister
DistrictDistrict Disaster Management Authority (DDMA), headed by the District Collector
ForceNational Disaster Response Force (NDRF)
  • The Disaster Management Act 2005 is the main law.
  • Relief funds: National and State Disaster Response Funds, and mitigation funds.
  • Cycle of disaster management: mitigation, preparedness, response, recovery.
  • Hazard is the event; vulnerability is how exposed people are; risk is the product of hazard and vulnerability, reduced by capacity.
  • Village level: panchayats, village secretariats and the agriculture assistant help in early warning, damage assessment and spreading advisories.

Worked examples

  • 1 mm rain over 1 hectare = 10,000 litres (10 m³). So 25 mm rain = 250,000 litres per hectare.
  • If normal seasonal rain is 800 mm and the actual is 560 mm, deficit = 240 ÷ 800 = 30%.
  • Energy at producer 20,000 J → at secondary consumer = 20,000 × 0.1 × 0.1 = 200 J.
  • If pesticide concentration is 0.1 ppm in water and rises ten times at each of three levels, the top level has 0.1 × 10³ = 100 ppm.
  • A paddy field of 2 ha sprayed with 500 litres per hectare needs 1,000 litres of spray fluid.

Practical environmental practice on the farm

Residue and waste: burning crop residue gives smoke, carbon dioxide and loss of soil organic matter. Alternatives are composting, mulching, incorporation using a mulcher or happy seeder, and use as fodder or bioenergy. Vermicompost and farmyard manure recycle farm waste into nutrient-rich manure.

Water use: micro irrigation (drip and sprinkler), rainwater harvesting through farm ponds, check dams and percolation tanks recharge groundwater. Reuse of treated waste water needs checking for salts and heavy metals. Over-pumping lowers water table and may cause salinity in coastal areas.

Integrated nutrient and pest management: soil-test-based fertiliser, biofertilisers (Rhizobium, Azotobacter, phosphate-solubilising bacteria), green manure, neem coated urea and bio-pesticides reduce harmful runoff. Pesticide label rules, waiting periods and safe disposal of containers protect users and consumers.

Coastal and climate risk in Andhra Pradesh: the long coastline brings cyclones, storm surge and seawater entry. Mangroves and shelter belts reduce wave and wind damage. Farmers use salt-tolerant and short-duration varieties, raised seedbeds, drainage channels and timely sowing after weather advisories. Early warning reaches farmers through mobile messages, village secretariats and local radio, and farmers should store seed and fodder safely before a forecast storm.

Exam traps

  • Mitigation reduces the cause; adaptation adjusts to the effect.
  • Eutrophication is nutrient enrichment, not heating of water.
  • Bio-magnification increases up the chain; dilution does not.
  • In-situ conservation is in the natural habitat; ex-situ is outside.
  • Montreal Protocol is for ozone; Paris Agreement is for climate.
  • NDMA is headed by the Prime Minister; DDMA by the Collector.
  • Hazard and disaster are not same: a disaster happens when a hazard hits a vulnerable population.
  • Acid rain pH is below 5.6, not above 7.

One-liners

  • The 10% law describes energy transfer between trophic levels.
  • Methane comes from flooded paddy and ruminants.
  • Nitrous oxide comes from nitrogen fertiliser.
  • CFCs damage the ozone layer.
  • The Montreal Protocol was adopted in 1987.
  • The Disaster Management Act is of 2005.
  • Gypsum is used to reclaim sodic soil.
  • Kolleru is a Ramsar wetland in Andhra Pradesh.
  • IMD gives weather warnings and agro advisories.
  • PMFBY is the crop insurance scheme.
  • NGT was set up in 2010.
  • Biosphere reserves have core, buffer and transition zones.

Practice questions

  1. Which organisms recycle nutrients in an ecosystem?

    1. Producers
    2. Primary consumers
    3. Tertiary consumers
    4. Decomposers
    Answer

    D. Decomposers

    Bacteria and fungi break down dead matter and return nutrients.

  2. Which of the following is an in-situ conservation method?

    1. Botanical garden
    2. Zoo
    3. Seed bank
    4. Biosphere reserve
    Answer

    D. Biosphere reserve

    In-situ means in the natural habitat.

  3. Eutrophication of a water body is caused by excess of

    1. Nitrogen and phosphorus
    2. Oxygen and hydrogen
    3. Sodium and chloride
    4. Calcium and magnesium
    Answer

    A. Nitrogen and phosphorus

    Nutrient enrichment causes algal bloom and oxygen loss.

  4. Bio-magnification means

    1. Breakdown of pesticide by sunlight
    2. Decrease of pollutant in water
    3. Increase in pollutant concentration along the food chain
    4. Growth of algae
    Answer

    C. Increase in pollutant concentration along the food chain

    Toxins accumulate and reach highest levels in top consumers.

  5. Acid rain has a pH value below about

    1. 5.6
    2. 7.0
    3. 6.5
    4. 8.2
    Answer

    A. 5.6

    Normal rain is slightly acidic at about 5.6; acid rain is lower.

  6. Which greenhouse gas is released from flooded paddy fields?

    1. Ozone
    2. Hydrogen sulphide
    3. Argon
    4. Methane
    Answer

    D. Methane

    Anaerobic soil bacteria produce methane.

  7. Nitrous oxide emissions in agriculture come mainly from

    1. Farm machinery sound
    2. Nitrogen fertiliser use
    3. Seed treatment with salt
    4. Rice husk
    Answer

    B. Nitrogen fertiliser use

    Soil microbes convert excess nitrogen to N2O.

  8. The substances mainly responsible for ozone layer depletion are

    1. Carbon monoxide
    2. Methane only
    3. CFCs
    4. Argon compounds
    Answer

    C. CFCs

    Chlorofluorocarbons release chlorine that destroys ozone.

  9. The Montreal Protocol deals with

    1. Substances that deplete the ozone layer
    2. Desertification
    3. Wetland protection
    4. Trade in wild animals
    Answer

    A. Substances that deplete the ozone layer

    It was adopted in 1987 to phase out ozone-depleting substances.

  10. The Paris Agreement on climate change was adopted in

    1. 1997
    2. 2015
    3. 1992
    4. 2005
    Answer

    B. 2015

    It aims to limit global warming well below 2 degrees C.

  11. The Disaster Management Act of India was enacted in

    1. 1986
    2. 2013
    3. 1974
    4. 2005
    Answer

    D. 2005

    The Disaster Management Act is of 2005.

  12. The National Disaster Management Authority is headed by the

    1. President
    2. Chief Justice
    3. Home Secretary
    4. Prime Minister
    Answer

    D. Prime Minister

    NDMA is chaired by the Prime Minister.

  13. The District Disaster Management Authority is chaired by the

    1. Chief Medical Officer
    2. Tahsildar
    3. District Collector
    4. Superintendent of Police
    Answer

    C. District Collector

    The Collector heads the DDMA.

  14. Pradhan Mantri Fasal Bima Yojana is a scheme for

    1. Soil testing
    2. Crop insurance
    3. Fertiliser subsidy
    4. Seed distribution
    Answer

    B. Crop insurance

    PMFBY insures farmers against crop loss from natural calamities, pests and diseases.

  15. Gypsum is used to reclaim

    1. Sodic (alkali) soils
    2. Acid soils
    3. Sandy soils
    4. Waterlogged laterite
    Answer

    A. Sodic (alkali) soils

    Calcium from gypsum replaces sodium on the soil complex.

  16. BOD of water is a measure of

    1. Oxygen needed by microbes to break down organic matter
    2. Hardness
    3. Salt content
    4. Acidity of water
    Answer

    A. Oxygen needed by microbes to break down organic matter

    High BOD indicates heavy organic pollution.

  17. Kolleru lake in Andhra Pradesh is a

    1. Salt pan
    2. Biosphere reserve for deserts
    3. Ramsar wetland
    4. Tiger reserve
    Answer

    C. Ramsar wetland

    Kolleru is a freshwater wetland of international importance (Ramsar site).

  18. The India Meteorological Department provides

    1. Seed certification
    2. Soil survey
    3. Crop insurance
    4. Weather forecasts and warnings
    Answer

    D. Weather forecasts and warnings

    IMD issues forecasts, cyclone warnings and agro advisories.

  19. The Environment (Protection) Act of India was passed in

    1. 1972
    2. 1986
    3. 2002
    4. 1981
    Answer

    B. 1986

    It is the umbrella environment law of 1986.

  20. Producers hold 10,000 J of energy. By the 10% law, the energy at the tertiary consumer level is

    1. 1000 J
    2. 10 J
    3. 100 J
    4. 1 J
    Answer

    B. 10 J

    10,000 -> 1000 -> 100 -> 10 J.

  21. At the producer level energy is 20,000 J. The energy at the secondary consumer is

    1. 20 J
    2. 2 J
    3. 2000 J
    4. 200 J
    Answer

    D. 200 J

    20,000 x 0.1 x 0.1 = 200 J.

  22. 1 mm of rain on 1 hectare equals how many litres of water?

    1. 100 litres
    2. 100,000 litres
    3. 10,000 litres
    4. 1,000 litres
    Answer

    C. 10,000 litres

    1 mm over 10,000 m2 = 10 m3 = 10,000 L.

  23. 25 mm of rain over one hectare is equal to

    1. 250,000 litres
    2. 2,500 litres
    3. 25,000 litres
    4. 2,500,000 litres
    Answer

    A. 250,000 litres

    25 x 10,000 = 250,000 L.

  24. Normal seasonal rainfall is 800 mm and actual rainfall is 560 mm. The deficit is

    1. 24%
    2. 40%
    3. 30%
    4. 70%
    Answer

    C. 30%

    240 / 800 x 100 = 30%.

  25. If the hydrogen ion concentration is 10^-5 mol per litre, the pH is

    1. 0.00001
    2. 5
    3. 9
    4. -5
    Answer

    B. 5

    pH = -log(10^-5) = 5.

  26. Compared with water of pH 7, water of pH 5 is how many times more acidic?

    1. 10 times
    2. 2 times
    3. 1000 times
    4. 100 times
    Answer

    D. 100 times

    Each pH unit is a ten-fold change; two units give 100 times.

  27. A pesticide is 0.1 ppm in water and becomes ten times more concentrated at each of three steps up the food chain. The top level has

    1. 100 ppm
    2. 1 ppm
    3. 0.3 ppm
    4. 10 ppm
    Answer

    A. 100 ppm

    0.1 x 10 x 10 x 10 = 100 ppm.

  28. A spray needs 500 litres per hectare. For 2 ha the volume needed is

    1. 250 litres
    2. 2500 litres
    3. 1000 litres
    4. 500 litres
    Answer

    C. 1000 litres

    500 x 2 = 1000 L.

  29. A solution has pH 3. Its hydrogen ion concentration is

    1. 0.001 mol per litre
    2. 0.003 mol per litre
    3. 3 mol per litre
    4. 0.0001 mol per litre
    Answer

    A. 0.001 mol per litre

    [H+] = 10^-3 = 0.001.

  30. Normal rainfall is 600 mm and actual rainfall is 450 mm. The deficit is

    1. 75%
    2. 15%
    3. 33%
    4. 25%
    Answer

    D. 25%

    150 / 600 x 100 = 25%.

  31. A 5 ha farm receives 40 mm of rain. The volume of water received is

    1. 400,000 litres
    2. 2,000,000 litres
    3. 200,000 litres
    4. 20,000,000 litres
    Answer

    B. 2,000,000 litres

    40 x 10,000 x 5 = 2,000,000 L.

  32. A farmer pays 2% premium on a sum insured of Rs 50,000. The premium is

    1. Rs 2,000
    2. Rs 100
    3. Rs 500
    4. Rs 1,000
    Answer

    D. Rs 1,000

    2/100 x 50,000 = 1,000.

  33. Consider the statements. Which of the statements is/are correct? 1. A food chain is a single path of feeding 2. A food web is made of many linked chains

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

  34. Consider the statements. Which of the statements is/are correct? 1. In-situ conservation protects species in their natural habitat 2. Seed banks are examples of in-situ conservation

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Seed banks are ex-situ.

  35. Consider the statements. Which of the statements is/are correct? 1. The Montreal Protocol is the main climate change convention 2. The Paris Agreement aims to hold warming well below 2 degrees C

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Montreal Protocol concerns ozone-depleting substances.

  36. Consider the statements. Which of the statements is/are correct? 1. NDMA is headed by the Chief Minister 2. DDMA is headed by the Governor

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    D. Neither 1 nor 2

    NDMA is chaired by the Prime Minister and DDMA by the Collector.

  37. Consider the statements. Which of the statements is/are correct? 1. Flooded paddy fields release methane 2. Ruminant animals are the main source of nitrous oxide

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Livestock mainly emit methane; nitrous oxide comes mainly from nitrogen fertiliser use.

  38. Consider the statements. Which of the statements is/are correct? 1. Eutrophication is nutrient enrichment causing algal bloom 2. A high BOD means polluted water

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

  39. Consider the statements. Which of the statements is/are correct? 1. Acid rain has pH above 7 2. Acid rain is formed from oxides of sulphur and nitrogen

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Acid rain has pH below 5.6.

  40. Consider the statements. Which of the statements is/are correct? 1. Mitigation means adjusting to the effects of climate change 2. Adaptation means cutting greenhouse gas emissions

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    D. Neither 1 nor 2

    The two definitions are reversed.

  41. Consider the statements. Which of the statements is/are correct? 1. Gypsum is used to reclaim sodic soil 2. Lime is used to reclaim alkaline soil

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Lime is used for acid soil.

  42. Consider the statements. Which of the statements is/are correct? 1. PMFBY covers crop loss from natural calamities 2. IMD issues cyclone warnings

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

  43. Consider the statements. Which of the statements is/are correct? 1. A biosphere reserve has only a core zone 2. A biosphere reserve has core, buffer and transition zones

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Biosphere reserves have three zones.

  44. Consider the statements. Which of the statements is/are correct? 1. A disaster occurs when a hazard strikes a vulnerable population 2. Short-duration crops are part of drought contingency plans

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

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